Since we're getting into discussions about success, skill, and metrics for such things, let me ask: what is the point of gear?
Suppose:
The content designers need to establish a baseline for which to design content difficulty around. They arbitrarily chose level 50. It's easier to balance around one level rather than several.
Content is created. 10% of the player population completes the content with the baseline stats. 90% fail, so presumably, they need additional tools to make it easier and allow for larger margins of player error (or they don't tweak it at all and just let players bash their heads against it until they win). Traditionally, this comes with "better gear", or stat supplements above what the baseline difficulty is designed around.
The following week, an additional 10% of the player base complete the content with their new stat boosts. I would assume players would argue that these players weren't as "skilled" or "as good as" the previous week's, because they needed a crutch. Gear is a crutch.
So why is it that people conflate gear/item level with success at all? What if clearing content provided no gear at all? What if all you got was a pat on the back, an achievement that pops up and says, YOU DEFEATED, and that was that? What if everyone played from the same toolset and baseline?
You may argue, hey, not everyone is that good, but everyone wants to see and complete content. Everyone wants to have fun doing this. What if the difficulty (going reductive with this and boiling it down to pure numbers for the sake of argument) goes down by 10% each week? What if it just depreciates, or players get a stronger and stronger buff the longer it takes to clear the dungeon, until they can?
What is the point of gear?
(I would also argue that gear itself ruins PVP. Imagine playing any PVP game, like Starcraft, where the toolsets are disparate, and the player you're going up against has units that just do 10% more everything. Where's the fun in that?)